1. Field of the Disclosure
The present disclosure relates to a light transmitting electrically conductive member and a method for patterning the same.
2. Description of the Related Art
A light transmitting electrically conductive member disposed at a front side of a display panel has been used as an electrostatic touch panel or the like.
In a related art light transmitting electrically conductive member, a light transmitting electrode layer is formed on a surface of a base material from indium tin oxide (ITO). However, this type of metal oxide is disadvantageously weak against a bending stress. In Japanese Unexamined Patent Application Publication No. 2010-507199, a light transmitting electrically conductive layer, which includes a resin layer and a network of electrically conductive nanowires embedded therein has been disclosed. Since being strong against an external physical force, such as a bending stress, the electrically conductive layer described above is suitably used for a light transmitting electrically conductive member, which includes a bending deformable resin film as a base material.
In the electrically conductive layer containing electrically conductive nanowires, a patterning may be performed by an etching step so that a non-electrically conductive region is partially formed by dissolving the electrically conductive nanowires. However, after the patterning is performed, there has been a problem in that between an electrically conductive region in which the electrically conductive nanowires remain and the non-electrically conductive region from which the electrically conductive nanowires are removed, a remarkable difference in optical characteristics is generated.
Accordingly, Japanese Unexamined Patent Application Publication No. 2010-507199 also discloses a step in which the electrically conductive nanowires are partially chemically transformed into non-electrically conductive nanowires or nanowires having a high resistivity. In the step described above, by applying an oxidizing agent to a region, which is required to be non-electrically conductive, silver nanowires are changed into an insoluble metal salt by modification so as to have non-electrically conductive properties.
In an electrically conductive layer including a network of electrically conductive nanowires, in order to ensure the electrical conductivity with a metal layer or the like to be formed on the electrically conductive layer, the nanowires are partially exposed to the surface thereof. Hence, when an oxidizing agent is applied to a region which is required to be non-electrically conductive, the nanowires exposed to the surface of the electrically conductive layer are formed into a metal oxide compound and remain in the form of a white cloudy material, and as a result, a problem in that the optical characteristics of the region which is required to be non-electrically conductive are degraded may arise.
In addition, in Japanese Unexamined Patent Application Publication No. 2010-507199, as the oxidizing agent, an oxide salt, such as a hypochlorite, or an organic oxidizing agent, such as tetracyanoquinodimethane (TCNQ), has been disclosed by way of example. However, those oxidizing agents each have not an adequate degree of permeation into an overcoat layer, which is a resin layer, in which a network of silver nanowires is embedded, and hence, patterning to partition the electrically conductive region from the non-electrically conductive region is difficult to be precisely controlled. In addition, when a lead layer is formed on the electrically conductive layer containing silver nanowires using a metal layer of copper or silver, a problem may arise in that this metal layer is liable to be damaged.